In standard wood frame house construction, the stud walls of an upper floor are built upon the floor and joists of the lower floor. The joint areas between the stud walls and the floor, as well as the band joist and sill plate of the floor, are usually covered by under sheathing or substantially rigid sheets of thermal insulation. Siding is then applied over the under sheathing to provide a finished outer wall. When the lumber used in the frame construction has a high moisture content it will be subject to drying over time with consequent shrinkage of the wood and separation between individual substructures such as the stud walls and the flooring on which they are built. In addition, the resulting space between the substructures may then collapse or settle resulting in a shorter distance across the joint area. This shrinkage and separation with eventual settling inevitably causes the under sheathing to buckle or separate which, in turn, causes the siding to be pushed out or separated and can result in air and water leakage of the wall and popping off of individual strips of the siding. The herein disclosed invention provides a way to maintain a good seal between the substructures for reduced air and water leakage and to avoid buckling or other damage to the under sheathing and siding.